Using the world as a chessboard and all the countries as chess pieces, he can prosper a country with one hand and destroy it with the other. He is the most famous person in the world, Mu Bai.
Luo Yue, as a princess, could have asked him to help her restore her country, but due to some strange combination of circumstances, she could only stay with him as a maid.
The fake princess constantly puts Mu Bai into danger, but the real princess Luo Yue has no way to prove her identity.
Finally one day, she said: Please accept me as your disciple and teach me how to govern the country and lead the army.